The present invention is drawn to methods for preparing cyclic carbamate and thiocarbamate compounds.
Methods for preparing cyanopyrrole-containing cyclic carbamate and thiocarbamate biaryls have been described in U.S. Pat. Nos. 6,509,334; 6,566,358; 6,436,929; 6,407,101; and 6,562,857. Such compounds are useful as progesterone receptor (PR) modulators, which are pharmaceutically useful for a variety of indications including contraception; the treatment and/or prevention of dysfunctional bleeding, uterine myometrial fibroids, uterine leiomyomata, endometriosis, benign prostatic hypertrophy, polycystic ovary syndrome, carcinomas, and adenocarcinomas; the synchronization of the estrus in livestock; and the stimulation of food intake.
Current methods for preparing cyclocarbamate compounds substituted at the 6-position with bromine substituents entail at least three steps and utilize expensive reagents, including 1,1-carbonyldiimidazole and 1,1-thiocarbonyldiimidazole.
Conversion of the cyclocarbamate to the cyclothiocarbamate further requires a fourth step utilizing a thionating agent. Such methods typically form a variety of impurities, including pyrrole thioamide impurities. These methods also entail many steps, are expensive, and are troublesome.
What is needed in the art are more efficient methods for preparing cyclocarbamate and cyclothiocarbamate compounds.